1. Field of the Invention
This invention relates to displays and in particular to the visual display of multiple time series data.
2. Background Information
The need to monitor multiple financial markets is well known. Participants of international securities investing have observed the increasing influence of one market over another, particularly during the minutes and hours immediately following the occurrence of some unexpected event of global proportion. Movement in one market tends to spread to adjacent markets almost instantaneously. When an event occurs at a time when some financial markets are closed, its expected impacts, as sometime measured by the opening gap, could be gauged by observing the behavior of those markets in session.
Traders often employ multiple intra-day charts, which plot the tick-by-tick changes of a particular stock market index or security, to track the international cross current. For example, during the Asia trading hours, participants may monitor the intra-day movement of Japan's Nikkei 225, Hong Kong's Hang Seng Index, and Australia's All Ordinary Index. Right after the afternoon sessions begin, traders in Asia would shift their attention to the imminent opening of the European markets, as they represent a more institutional phenomenon. European investors, on the other hand, often decide their opening bids and offers based on the behavior of the Asian markets.
In one explanation, the need to monitor multiple markets is said to arise because traders in one region of the world often look for clues from foreign markets that may reinforce or reverse the existing trends in their home market. Empirically, this type of short-term interdependence has deepened over the years, particularly among the five highly liquid, actively traded exchanges, namely, New York, Tokyo, Hong Kong, London, and Frankfurt.
Although the known display of multiple, standalone tick-by-tick charts on a single computer screen is rich with current market information they have disadvantages which hamper rapid decision making. The disadvantages are set out below.
Firstly, it is difficult to look back at past trading interaction between different markets and instruments. For example, Dow Jones Industrial Average may have in the past week exhibited greater daily influence upon the UK FTSE 100 index than on the German DAX Index. Such pattern would not be obvious by looking at their individual single day tick behavior on a standalone basis.
Secondly, existing charts tend to ignore the fact that different markets have different trading hours. There are non-overlapping periods where the source of influence on a market is different. An overlaid chart plotted against a single time line can be constructed to display multiple markets. However, a much larger amount of real time data is needed. If a user monitors six markets over the course of a day and if he/she chooses a minute plot, one period will require more than 2,000 data points. Further, such displays are confusing and difficult to extend beyond one period. Multiple lines criss-crossing in a narrow area of a multi-period chart are difficult to read.
Thirdly, as a practical matter, economy of display area is an issue. Both the tick chart and the overlaid plot take up a large portion of the computer screen, making it difficult to show other live information.
Finally, for analysts examining the past behavior of stock markets, it is currently difficult to reconstruct the past market interaction using currently available historic database. Most of these databases keep no more than four data points (open, high, low, close) on any particular day.